Investigation on stator winding faults of induction motor

Abstract

Three phase induction motor plays a very important role in the daily activities in several organizations and industries. For example, the air-conditioning system in Nanyang Technological University uses motors to run compressors and enable ventilation. Even the lifts systems rely on motor to actuate a cable mechanism that enables transfer of people and goods across different level.

By monitoring the faults of motor, the fault can be detected early before the failure or shutdown of motor. Therefore, with the reduction of losses caused by motor faults, there will be an increase in production time, leading to an overall decrease in operation cost. But many companies practice the traditional methods of monitoring a motor system, whereby action is only taken when the motor fails to operate. Meaning, instead of a preventive solution, the company literally waits for a fault to happen before calling for motor supplier and request for assistance. This can be expensive policy, as payment will then be required to pay for the servicing or inspection.

There are many methods to of motor condition monitoring to detect faults in an induction motor. There are Vibration Analysis, Motor Current Signature Analysis (MCSA), Electromagnetic Field Monitoring, Temperature or Infrared Measurement, Partial Discharge Measurement, Chemical Analysis, Acoustic Noise Measurement and lastly Radio Frequency Emission Monitoring. Of all these methods, the most common ones are the Vibration Analysis and Motor Current Signature Analysis methods. It is because these two methods can detect almost similar motor faults such as eccentricity, bearing and rotor faults. Out of these two methods, only MCSA method can detect stator winding faults.

Stator winding faults consist of open and short circuit faults. In short circuit faults, there are turn to turn fault, coil to coil fault, and phase to phase faults. All these faults are a short circuit of faults.

Thus in this project, the author will monitor condition of the induction motor by design and fabricating the test bed followed by carry out the testing of stator winding turn to turn fault using MCSA method.